Using OpenAL-soft or Rapture3D with Unity 4

Hi, We want to integrate an audio engine that can do 3D sound (binaural or ambisonic) into Unity 4 for our next project. The best option appears to be OpenAL-soft or Rapture3D. Has anyone tried integrating a different audio engine into Unity? Is there an existing OpenAL integration, or a straight forward way to present the same/extended editor interface with a different audio engine. Is there an alternative you'd recommend over OpenAL(chatted to the FMOD team, i know it doesn't have support, I can't find any details about WWise)

Thanks